A. Field of the Invention
The present invention relates generally to the communications field, and, more particularly to a blank module with conduit retainer.
B. Description of the Related Art
Presently, it is a problem in the field of communication cable installation to ensure the precise placement of the communication cable without the possibility of damage or performance degradation to the communication cable by the provision of tight bends, or inappropriate use of fasteners, or inadequate support to the communication cable. Such communication cables include conventional telephone cable having a plurality of copper conductors, coaxial cable, optical fiber, or the like. In all of these applications, the minimum radius of curvature of the communication cable is well defined, and bending the communication cable in a tighter bend can cause damage to the communication medium housed within the cable. The installer of communication cable is thus faced with the problem of routing the communication cable over surfaces, which typically include sharp bends, without over bending the communication cable, yet also securing the communication cable to these surfaces in a manner to ensure protection from damage.
This problem is further heightened when fiber optic cables are used. Glass fibers used in such cables are easily damaged when bent too sharply and require observation of a minimum bend radius to operate within required performance specifications. The minimum bend radius of a fiber optic cable depends upon a variety of factors, including the signal handled by the fiber optic cable, the style of the fiber optic cable, and equipment to which fiber optic cable is connected.
Inappropriately routed and damaged fiber optic cables may lead to a reduction in the signal transmission quality of the cables. Accordingly, fiber optic cables are evaluated to determine their minimum bend radius. As long as a fiber optic cable is bent at a radius that is equal to or greater than the minimum bend radius, there should be no reduction in the transmission quality of the cable. If a fiber optic cable is bent at a radius below the minimum bend radius determined for such cable, there is a potential for a reduction in signal transmission quality through the bend. The greater a fiber optic cable is bent below its minimum bend radius, the greater the potential for breaking the fiber(s) contained in the cable.
Optical communication equipment is typically housed in bays, which include a rectangular frame having dimensions conforming to a particular standard, such as the Network Equipment Building Standard (NEBS). NEBS was originally developed by Bell Telephone Laboratories in the 1970s and expanded by Bellcore. Long a requirement for equipment used in the Central Office in the North American Public Switched Network, the NEBS criteria have become a universal measure of network product excellence.
NEBS covers a large range of requirements including criteria for personnel safety, protection of property, and operational continuity. NEBS covers both physical requirements including: space planning, temperature, humidity, fire, earthquake, vibration, transportation, acoustical, air quality and illumination; and electrical criteria including: electrostatic discharge (ESD), electromagnetic interference (EMI), lightning and AC power fault, steady state power induction, corrosion, DC potential difference, electrical safety and bonding and grounding. The term xe2x80x9celectrostatic dischargexe2x80x9d or xe2x80x9cESDxe2x80x9d, as used herein, refers to the rapid, spontaneous transfer of electrostatic charge induced by a high electrostatic field. Usually the charge flows through a spark (static discharge) between two bodies at different electrostatic potentials as they approach one another.
An optical communications equipment frame further typically has a plurality of shelves, each having one or more slots for accommodating circuit boards or cards that have optical and electrical components associated with a communication network mounted thereon. The components include, but are not necessarily limited to lasers, photodetectors, optical amplifiers, switching elements, add/drop multiplexers etc. In addition, fiber optic cables typically connect to one or more components.
One type of component used in optical communications equipment is a line module. A line module typically accommodates a circuit board or card, and a plurality of optical modules that have optical and electrical components mounted thereon. The line module has an opening for receiving the optical modules so that they may interconnect with the circuit board or card provided on the line module. A line module may also have components, normally contained on the optical modules, integrated directly into the line module. This type of line module has openings for optical interconnections, but no openings for optical modules.
Ideally, each shelf of an optical communications equipment frame will be fully populated with line modules with each line module fully populated with optical modules. However, the slots of each shelf typically are not fully populated, thereby resulting in the use of blank (dummy) line modules (alternatively called line module blanks) as well as with the use of blank (dummy) optical modules (alternatively called optical module blanks). Such blank modules are structurally configured the same way as modules, which contain electrical components, but specifically do not contain the typical electrical components found within the modules. These blank modules typically are used due to the equipment requirements of the user or the desire of the user is to leave room for future expansion of the communications system.
It also may be desirable to route all of the optical fibers (alternatively called fiber optic cables) to be used in a fully-populated communications equipment frame, even if line module blanks or partially populated line modules with optical module blanks are used, to thereby prevent over-handling and potentially damaging the fiber optic cables. Routing all of the fiber optic cables from the beginning also ensures that the cables will already be available when blank modules are replaced with true modules.
Currently in the installation process one of two events may occur, either the fiber optic cables are not provided for the unused port spaces in optical module blanks and line module blanks, or all the fiber optic cables are provided and the unused fiber optic cables are left to hang within the equipment frame. If the cables are not provided, then they need to be routed when additional components are installed in the equipment frame, increasing the potential damage that may be caused to over-handled existing fiber optic cables. If the fiber optic cables are provided and the unused fiber optic cables are hanging in the equipment frame, they may be damaged when line modules are moved in and out of adjacent slots in the equipment frame, or when the door to the equipment is opened or closed. Additionally, the installer needs to be able to verify that the fiber optic cables are of adequate length to reach the ports when optical modules are added.
The same holds true when other optical or electrical conduits are used. For example, during installation of electrical conduits, such as telephone cable having a plurality of copper conductors, coaxial cable, or the like, one of the two events discussed above may occur. As used herein, the term xe2x80x9cconduitxe2x80x9d refers to any electrical, optical, or other like media used to transmit and receive data or information from one point to another.
Thus, there is a need in the art to provide an inexpensive means for retaining conduits within a system, when blank modules are used, to permit an installer to route all of the desired conduits for a communications frame, to verify the conduits are routed to the correct length and to prevent the conduits from being damaged while they are stored within the frame.
The present invention solves the problems of the related art by providing blank modules that, when inserted within a slot of a bay (or shelf) of a communications system housing, allow an installer to route conduits within a communications frame to a desired length and have the conduits stored in a manner that is analogous to conduits that are used. This prevents the increased chance of the conduits being damaged from additional handling or inappropriate storage.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating various embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.